This isn't a Theory
by ChibiSteve-hisvoiceislove
Summary: Tony is pregnant with Bruce's baby. mpreg. -UPDATED 12/9/12 WILL UPDATE BEFORE NEW YEAR-
1. Prologue

**Prologue**

Tony couldn't believe what he was seeing on the sonogram. He had thought he had appendicitis so he went up to the hospital floor of Stark towers and performed a sonogram. What he saw wasn't appendicitis.

It was a baby.

Bruce's baby…


	2. Chapter One: Conception

It had been two or three months earlier. He had just started going steady with Bruce and after numerous tests, they were sure that the Other Guy wouldn't come out if Bruce topped. Tony stripped in front of the doctor, waving his ass at him. Bruce stripped slowly as Tony walked toward him. Bruce got up with a start and threw Tony on the nearest table, and flipped him over.

"You are too sexy for your own good, Anthony…" Bruce growled, getting on top of the billionaire. Tony felt the color drain from his face. Was he going to become the Hulk? Tony felt his legs being spread and a tongue swirling around his entrance. He let out a drawn out, soft moan. He heard Bruce chuckle down by his ass and felt Bruce's hands move around to his cock and start pumping him as his tongue penetrated past his ass cheeks.

Tony felt himself slowly surrendering to Bruce. He became a mess of moans, wriggling lightly under Bruce's grasp. Bruce pulled his face away from Tony's ass and soon Tony was penetrated by something that was definitely too big to fit. This wasn't part of their tests. His cock couldn't have been this big then, could it? It felt too large, but Tony didn't care. It felt insanely good, being filled with Bruce. He screamed the doctor's name, slamming his face into the table. There would be bruises tomorrow.

Bruce held onto Tony's waist tightly, digging his nails in to keep his calm. He thrust slowly at first, letting Tony adjust to the size, that is until Tony started screaming at him to move; faster, harder, and rougher. Bruce didn't want to hurt Tony so he slowly increased his speed, until he was thrusting hard and rough into the genius. Tony screamed with each thrust, coming close to his climax. Bruce felt Tony's walls tighten around his cock, and thrust rougher. With a scream of the doctor's name, Tony came, hard, onto the table. Bruce thrust a few times until he released deep inside Tony, trying not to let any of his release escape Tony.

After an hour more of making out, Tony had a meeting to attend to and he left the lab, walking funny because of the pain in his ass. But, as he exited, he decided that it was totally worth it.


	3. Chapter Two: The Fearsome

**Chapter Two: The Fearsome**

Tony was afraid to tell Bruce that he was nearly three months pregnant with his child. He wandered down to the kitchen of the tower, suddenly craving yogurt and pretzels. Much to his dismay, Bruce was in the kitchen, eating Cheerios. Tony walked by and kissed his boyfriend on the cheek.

"Where were you this morning, love?" Bruce turned in his seat, watching Tony get the yogurt from the fridge. Tony gulped. His boyfriend noticed everything, especially when he woke up and Tony wasn't there. There was no way in hell that Tony was going to get out of this.

"I didn't feel well so I went up to the hospital floor to check myself out." Tony shrugged and grabbed the bucket of pretzels off the top of the fridge, then sat at the island next to his boyfriend, opening the yogurt and dipping a pretzel in. He felt Bruce's eyes on him.

"Well… are you okay?" Bruce asked, inspecting Tony's features. Tony nodded and ate quickly, suddenly starving. "You seem different this morning, love. Are you sure you're okay?"

"Yeah… I thought I had appendicitis at first… and then turns out that wasn't it." Tony replied nonchalantly. Hopefully, Bruce wouldn't ask any more questions. Knowing his boyfriend, however, Tony was braced for more.

"Then what was it? Was it gall bladder or irregular bowel movements? Tony… tell me what's wrong so I can help you." Bruce pleaded. Tony sighed. He was going to have to tell Bruce the truth eventually. He was going to be showing in a month or two. Tony inhaled deeply then spilled it.

"I'm pregnant. With your child. I don't know how it happened. It just did. The baby is growing in my appendix and I'm scared, Bruce. I'm so fucking scared. If you want to leave me do it before I start having mood swings. I am keeping the baby even if it kills me. Even if there is a mini Hulk growing in me it is still our child. It is our baby. It is a figment of our love and I can't get rid of that." He spoke quickly but clearly, and then looked at Bruce for his reaction.

Any hint of a smile that Bruce had before had disappeared. The look on the doctor's face was genuine worry that Tony DID have a mini Hulk growing in him. He couldn't lose his boyfriend, not like this. Bruce stood up. "We are getting that monster out of you before you get killed."

**AU: Welp. Bruce is kind of an asshole. I didn't mean for it to turn out this way! *dies in the corner***

**ANYWAYS. Thank you for your support~ I will be updating this next Tuesday. So be patient and please continue reviewing so I can make this even more amazing!**


	4. Chapter Three: Ours

**Chapter Three: Ours**

Tony stared at his boyfriend. "No. Didn't you just hear me? I don't care if it's a mini Hulk! It is our baby!" Tony took Bruce's hand and put it over his stomach. Tears sat on the edge of Tony's eyes. "Do not make me get rid of our baby, Bruce. Please. If you love me…"

"If I love you I'll let this thing kill you slowly! You'll never be able to give birth to a mini Hulk!" Bruce started yelling, taking a step back. Tony got up and stepped away to the alarm system, his hand on the lever.

"I would be able to do it." Tony replied calmly. "Please Bruce, calm down. I would be able to give birth to the baby. I want a baby, Bruce. But I can't do this without you! I'm so scared..." Tony whimpered lightly, seeing Bruce's eyes turn dark. "Calm down, Bruce… please…"

"Let me see the baby on the sonogram. I may be able to tell if it will be a mini Hulk. It could be like me and only turn into a Hulk when it is angry…" Bruce said, calming down after seeing Tony's tears. Tony nodded slowly. "If the baby is a mini Hulk will you promise me that you will have a C-section birth? Not a natural?"

Tony looked down at his feet and walked back up to the hospital floor, Bruce following. He nodded slowly and felt Bruce's hand take his. "If that's what it takes to keep you by my side, Bruce…" Bruce smiled and walked next to Tony.

"I love you, you know that? I'm sorry I freaked out. I just… I'm scared for you." Bruce sighed. Tony stopped walking and looked at Bruce. "I'm madly in love with you. If something were to happen…" Bruce stopped talking when he felt Tony's hands on his cheeks.

"Nothing is going to happen." The genius smiled lightly. "I have you by my side, don't I?" Tony kissed Bruce softly and then started walking again. Bruce didn't move. Tony sighed and turned to his boyfriend. "I love you too, Bruce." Bruce smiled and started walking alongside Tony. "So... Should we get married?"

**AN: so. basically. Tony is really out of character but he's pregnant so justified? not really i guess. anyways. a lot of people have been anticipating this chapter so hopefully i've done good. probably not. anyways. the update next week may be in the early morning. or in the late night. and then two weeks from today there will not be an update because i have my county fair and i have a pig so. yeah. please continue supporting Brony~ and review! so i can make it better.**


	5. Chapter Four: Steady Heartbeats

**Chapter Four: Steady Heartbeats**

Bruce stopped again. Marriage… was Tony being serious? They'd only been dating for three months. But… Tony was pregnant. And as much as he thought that they shouldn't get married, he figured they'd probably have to. Their child's life would be weird enough, with a genius as a mother and a rage monster as a father. The child should probably have married parents.

Tony was waving a hand in front of his boyfriend's face. "Bruce…?" He cooed softly. All he did was ask if they should get married… "Bruce, honey…" Tony smirked. He had made the other man freeze so he decided to poke him with a pen he had in his pocket.

"OW!" Bruce jumped. Tony smiled. Bruce eyed the taller man carefully and sighed. "Let's hurry and get the sonogram." He walked ahead of Tony. Tony sighed. Maybe it wasn't a good idea to ask that. He followed behind Bruce until they got to the hospital floor and went to the sonogram room. Tony stripped himself and sat in the chair, legs bent at the knee and arms crossed behind his head. He shivered when he felt the cold fluid being put on his stomach by his boyfriend. "You said in your appendix right?" Bruce asked. Tony nodded and watched the sexy man in glasses inspect the sonogram. Tony stared up at the ceiling.

"Hurry up, Bruce…" Tony muttered. "I don't like being naked for too long." Tony pointed out. Bruce was still looking for the appendix. He found it and left the sonogram in the same place, turning to Tony and spreading his legs more.

"I need to put a heart monitor in to check if the baby is okay…" Bruce muttered. Tony looked at him worriedly. "The baby is fine. It's just standard procedure, Tony. In India I was the only one in town who had the machinery to do this and I helped many women with their babies." Tony still had a worried look. "The baby isn't a mini Hulk." Bruce replied to his boyfriend's endless stares. "This is going to hurt a little." Bruce stuck a few wires up Tony's ass, making the genius whimper, and looked at the monitor, until he saw them at the appendix. He attached them to the appendix and then the two could hear a steady heartbeat. Tony leaned back in the chair, relieved.

**AN: well, folks! That's it for two weeks~ I will be updating on the 14th of August. wish me luck at fair!**


	6. Chapter Five: Symptoms

**Chapter Five: Symptoms**

Tony wandered down to the lab one morning and saw a note on one of the tables.

_Dear Tony,_

_I've gone out. I'll be back this afternoon. I have a surprise for you tonight. Don't do anything reckless, you are carrying my baby. I love you._

_Love, Bruce._

Tony sighed and rubbed his small baby bump. What was he going to do all day without his boyfriend? He wandered back out of the lab and up to the kitchen, craving something sweet. Natasha and Clint were sitting at the table, eating breakfast.

Natasha looked up. "Oh, look who it is." She smirked. Tony was afraid of telling the other Avengers about the baby, and he had made sure to hide it. "You've been putting some weight on, Tony." Tony frowned and looked down at himself.

"The Science Brothers are having a dry spell, that's why." Clint replied. "If they were having sex constantly, he would still be in great shape. Tony eats at his sexual desires."

"I've seen him vomiting every morning. Wouldn't that make him skinnier?" Natasha questioned. Tony's frown was getting deeper. They shouldn't be discussing this. It's none of their business. Tony wandered to the fridge and looked at the fresh batch of cookies with a note on top that says _Tony's Cookies._ Tony stuffed one in his mouth and grabbed three more.

"Bruce has been baking those every morning. He knows you like them." Clint smiled. Tony settled into a chair and finished the first cookie. Tony's main cravings were for sweets, and Bruce was making the cookies every morning for him.

"What's with that stupid smile on your face?" Natasha tilted her head at him. "You look like a teenage girl in love." Tony shrugged and ate his second cookie. The assassins traded looks and then left the kitchen after disposing of their trash. Tony leaned back in his seat. His symptoms hadn't been that bad yet. He had mild morning sickness, but only a few times a week. He hadn't had any mood swings yet, but his cravings were out of control. They ranged from sweets in the morning to spicy in the afternoon and salty at night.

Tony sighed and rubbed his stomach, and then got up to go for a light swim, something he and Bruce did every morning. Bruce wanted him to do a water birth, so they were getting as used to the water as possible. Tony found it harder as time went on to swim on the deeper end, which made sense. He liked staying in the shallow side when Bruce was out, just in case.

After his swim, Tony wandered to the lab again and found a wrapped box that he hadn't noticed before. He pulled the gold ribbon off and ripped the red wrapping paper to reveal a box. He opened the box gently and took out the contents.

The first thing he took out was a red and gold pacifier. Tony bit his lip and fought the tears that were brimming on his eyes. Bruce was already getting the baby things. Tony was suddenly falling deeper in love with the father of his child. To Tony, this meant that Bruce wants the baby as much as Tony does.

The second thing was a one-piece clothing item. On the front it said _My Mommy is a genius… _and on the back it said _…but my Daddy is the Hulk_. Tony bit his lip harder, making blood trickle down his chin. Tears were streaming down Tony's face. He dropped the cloth onto the table and dug through the box.

The last thing Tony pulled out was a two-sided stuffed animal. On one side it was Iron Man, and on the other was the Hulk. Tony collapsed to his knees and started sobbing, holding the stuffed animal tightly to him.

The lab doors opened and Bruce walked in. He had figured that Tony was already out for the day, but when he heard the sobbing his heart stopped. He walked over to one of the tables and found Tony crying under the table, hugging the stuffed animal.

"Tony…?" Bruce murmured softly, getting to his knees. "Honey, are you okay?" Suddenly he was hugged by the genius. He hugged back, worried lightly about the reason for his boyfriends' tears.

"I love you. So much. Thank you for this. Thank you. I'm so happy." Tony cried into Bruce's shoulder. Bruce let out a sigh of relief. It was only Tony's emotions that had caused him to cry like that.

"I love you too, Tony."

**AN: so i tried to make this chapter longer... and more detailed. i hope i succeeded! also this is the last of my chapters that were pre-written so i may not update next week! just a warning~! if i have enough creative juices i will write chapters on thorsday (what my girlfriend and i call Thursday because we're weird like it's odd just writing thursday instead of thorsday now lol) and i still have to write the last chapter of SCLHR so. anyways. please review and continue supporting TINAT.**


	7. Chapter Six: Hulked Out

**Chapter Six: Hulked Out**

Tony was lying in bed, hugging the stuffed animal. Bruce had gone out again after he stopped crying, and now Tony was blasting Linkin Park through the loudspeakers in their shared room, waiting. He glanced at the clock and sighed. Bruce was supposed to be back by then… but he wasn't.

Suddenly the music stopped playing and the lights in his room had gone out. He sat up, startled, and hugged the stuffed animal closer to him. It couldn't have been a black out, his tower ran on its own electricity… unless someone knocked it out. He bit his lip. The only ones capable of doing that were Thor and Bruce, and Thor was in Asgard. He grabbed his phone with shaking hands and tried to hit speed dial one. He missed and hit speed dial 2, and called Steve. He hung up rapidly.

He threw the phone at the bed and it bounced onto the floor. He was having a panic attack. The doors open on power and he was stranded. "J-Jarvis…" He cried. There was no response. The door slammed open and Pepper ran in.

"Tony, we need to get out of here, now!" She shrieked at him, flailing her arms. Tony stared at her, shaking. His eyes questioned her. "Bruce hulked out on the second floor. Loki played a prank on him… and he got mad. Now he's making a mess. Tasha and Clint are on their way." She walked over to him and held out her hand. "The helicopter is on the roof." Tony felt himself nod and stand up, clutching the stuffed animal closer, and follow her to the roof. He heard a roar and shuddered. When he got into the helicopter it took off, and he fell asleep listening to gunshots and explosions.

When he woke up, he was lying on an uncomfortable bed. He sat up abruptly and looked around to see Steve and Thor. He looked down at himself and saw only sweats, he wasn't wearing a shirt and his baby bulge was evident. He glanced at them. "What happened to Bruce?" Steve looked at him sadly. "Steven Rogers you answer me right now!" He yelled, getting off the bed quickly.

"You should be laying down in your condition!" Thor ordered loudly. Tony looked shocked. Thor was never that orderly… He watched as Thor passed a hand through his hair. "I'm sorry, Tony. Captain… you should tell him."

"Tell me what?" Tony asked, walking over to the table they were sitting at. He sat between the two. Steve took his hand. Tony bit his lip.

"Bruce has been deemed unfit to live in Stark tower. He's been sent to a deserted island to be exiled for the rest of his life." He explained slowly and softly. Tony pulled his hand away from Steve's and shook his head.

"No. Bring him back! I need him! He's the father of my baby, and I can't do this without him!" Tony screamed, standing up. Thor got up and sighed.

"We were going to. But he is not returning to his normal self. Dr. Selvig was running tests and we fear he is permanently the Hulk." He explains. Tony ran out of the hut and found himself in a giant dome. He felt Thor beside him. "We are on the island at the moment, but as soon as Selvig finishes running the tests, we will be leaving." He said as a low roar shook the dome.

"You are familiar with the dome, right Mr. Stark?" A voice said. He turned and saw Director Fury. "It is made of the same material as the cage on the hellicarrier. I had this made in the event that Dr. Banner became permanently unstable." Tony inhaled sharply.

"Let me talk to him." He ordered. Steve walked out and placed a hand on the billionaire's shoulder.

"He could hurt you, and you're pregnant. Bruce may be sweet and gentle with you, but the Hulk might not care that you are with child." The captain murmured. Tony let out a little whimper and pouted.

"I've dealt with the Hulk several times. If I could just get my suit and go to him I could convince him…" Tony tried to convince them but they all shook their heads. He felt a breeze and then Clint was in front of him. He jumped.

"I think that could work, Director Fury." The archer commented. "I'll go with him just in case. I am the one that took him down at the tower, if Tony is in trouble I can take him down again. That is why I made these arrows." He smiled, pulling out one of the green arrows. "It has poison in it, but it only makes him go unconscious. Selvig is trying to make one that would allow him to go back to being himself." Fury sighed.

"Fine. Thor, go get the Iron Man suit." He ordered, and then walked away. Thor went to the building next to the hut. Steve looked at Tony and sighed. Tony turned to his best friend.

"Why didn't you tell me?" Steve asked sadly. Tony looked down. "I know I'm old-fashioned but I wouldn't shun you for being a pregnant man, Tony. I'm 100% on board, and if you need anything just tell me. I'm here for you."

"I need you to help me get in the suit."

**AN: oh my what have i done ;a; anyways starting this week i will be updating on sundays because school starts two weeks from tuesday and i have things to do this tuesday and next~ so. i hope you guys enjoyed this chapter and please review! **


	8. Chapter Seven: Stress

**AN: I know it's long overdue, but here is chapter seven!**

**Chapter Seven: Stress**

Tony soon found himself in his suit, dropping Clint in a tree and then going towards the green monster. He stopped right in front of his giant boyfriend. "Hey, you're not point break!" He faked a chuckle. Hulk roared at him. "Oi! Are you trying to be scary? You don't scare me, Bruce." The monster's face softened.

"Tony… safe?" He spoke quietly, but it was more like yelling to the genius. He sighed and bit his lip. "Baby… healthy?" Tony looked up at him. This wasn't the Hulk. The Hulk was a monster. This was Bruce. The Bruce that cared so much about Tony. The Bruce that was going to be an amazing father.

"I'm fine, and the baby is fine. I would like it if you went back to being my loving boyfriend, you know. I almost had a panic attack last night." Tony laughed. The Hulk looked away. Tony watched him carefully.

"Hulk sorry." The monster spoke. Tony flew up to Bruce's face and brought the face portion of the suit up so his face was showing, and he kissed the Hulk's green cheek. He flew back a little and watched as his boyfriend slowly became his boyfriend again. He flew down to the ground when it was Bruce again and caught the doctor before he passed out. He felt a presence next to him and looked to see Clint.

"I've got him, Tony. Go get a bed ready for him." Clint ordered as Steve came out of a bush. The billionaire nodded and flew off, towards the dome.

Three days later Bruce was finally allowed to see Tony. The billionaire was sitting in the middle of their bed, legs crossed, playing with his hands, when the doctor walked in. Tony glanced up and inspected Bruce's face.

"I'm sorry, Tony…" He whispered. Tony slid himself off the bed and walked over to Bruce, wrapping his arms around the shorter man. Bruce glanced up at Tony and bit his lip.

"I love you." Tony replied softly before planting a soft kiss on Bruce's lips. The scientist felt Tony's tongue licking his lips and hesitated before opening his mouth and allowing Tony to penetrate. Tony gently pushed Bruce to the wall and started to unbutton the shirt that the doctor was wearing when Bruce pushed his boyfriend away from him.

"No, Tony. I'm not going to have sex with you, not after what happened." Bruce ordered harshly. Tony whimpered and pushed past the doctor and left the room, tears starting to trail down his face. Bruce chased after Tony. "You can't just leave because I don't want sex!"

"It's not going to hurt me!" Tony spat at Bruce. "You're not going to hurt me, Bruce! Why won't you give me what I need right now? I need you!"

"You need to be safe, for the baby." Bruce whispered. Tony slammed his fist into the wall.

"I'm just the one with a baby now aren't I? I don't have feelings, do I? I don't get to enjoy myself anymore, do I? Then maybe I should just leave you out of my life and find someone who will actually give me what I need right now." Tony replied harshly.

"Tony…" Bruce tried to hug Tony but got a slap.

"I don't need any more stress right now." Tony walked away, practically running, and ran into Steve.

"Tony?" Steve whispered, "Why are you crying?" He then saw Bruce staring at the ground and frowned. "Did he do something to you?!" Steve walked up to the short man. Tony watched quietly. "What did you do!?"

"I denied him sex and he's upset with me." Bruce muttered. Steve frowned deeper.

"He's pregnant. Sex isn't going to hurt him, Bruce. He needs a stress-reliever, and all you care about is making sure the baby is okay. He has feelings too, and he needs you right now," The captain sighed. "You put him through so much the other day, he just needs to feel your arms around him because without you what is he? Without you, he's just a man with a baby growing inside. With you, he's loved, and happy. Well, maybe not anymore. Now he's stressed and worried. He hasn't slept in three days because we wouldn't let him see you. THAT is what's hurting the baby. If all you care about is how the baby is, you don't deserve to have Tony."

Tony looked at Steve carefully. His best friend was lecturing the man he loved because he only wanted to see Tony happy. Steve was a brilliant man; he was his best friend, after all. Tony only picked the best people to be his friends. He was lost in thought when he felt two hands take one of his. He looked around and in front of him, on one knee, was… Steve?

**AN: HOLY FUCK WHAT HAVE I DONE? Uhm, i'll try and update before the new year, I'm so sorry this took so long to update, it's been a long three and a half months. Please leave comments and predictions on what's going to happen! ~Mandy~**


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